Control system



April y 3, 1934. H. E. wuLFlNG CONTROL SYSTEM Filed May 28, 1924 INVENTOR ATTORNEY Har/"g E Wzl/19kg.

Patented Apr. 3, 1934 UNITED YSTATES PATENT OFFICE Application May 28, 1924, Serial No. 716,359

16 Claims.

My invention relates, in general, to control systems and more particularly to systems for selectively controlling and supervising, from a central point, remotely-disposed electrical equipj ment.

One of the objects of my invention is to provide selective circuits whereby a dispatcher at a central station is enabled to select and operate apparatus units in a distant electric station or substation.

Another object of my invention is to provide means for apprising the dispatcher of the operation of the selected unit.

Another object of my invention is to provide synchronously-operating selecting devices for selecting an apparatus unit at the distant station.

Another object of my invention is to provide means for calling the attention of the dispatcher in the event that the selecting devices get out of j synchronism.

Another object of my invention is to provide means whereby the dispatcher is able to resynchronize the selecting devices.

A still further object of my invention is to 'j provide means for indicating to the dispatcher when an apparatus unit is operated at the substation either manually by an operator thereat or automatically by devices responsive to circuit conditions at the substation.

There are other objects of the invention which, together with the foregoing, will be described in the detailed specication which is to follow.

Referring now to the drawing, suflicient apparatus and circuits have` been shown, by means of conventional diagrams, to enable my invention to be readily explained and understood.

The apparatus and circuits located to the left of the dotted line are those in the dispatchers oice, while the apparatus and circuits located to the right of the dotted line are those in a remote station.

In carrying out my invention, I provide a rotary selecting switch at both the dispatchers office and substation. In addition, two keys are provided by which the dispatcher is enabled to operate a circuit interrupter, or other apparatus unit, at the substation. An operating switch is provided whereby the dispatcher is enabled to control the operation of the rotary switches at both the dispatchers oiiice and station in a step` dispatchers office for enabling the dispatcher to synchronize the operation of the selector switches. A signalling lamp is also provided at the dispatchers oflice whereby the position of the apparatus units at the station may be ascertained.

At. the substation, relays are provided which may be selected by the operation of the rotary selector switch thereat tooperate the apparatus units in the station.

Briefly, the operation of my invention proceeds as follows. In the event that the dispatcher desires to operate a particular apparatusV unit at the station, he will operate his manual control key until the wipers of the selector switch at the dispatchers oftlce are stepped into a position corresponding to the particular apparatus unit desired. ,The wipers of the rotary switch are so positioned that they are visible to the dispatcher, and the position of the wipers is indicated at all times by a scale and a pointer in a well known manner. The wipers of the rotary switch at the station are stepped in synchronism with the wipers of the switch at the dispatchers office. They are, consequently, in the same relative position with respect to their bank contacts.

By operating the closing or tripping key, the dispatcher is enabled to close or trip the selected circuit interrupter. The operation of the interrupter causes the signalling lamp at the dispatchers cnice to indicate the operation of the unit. The dispatcher now operates the manual control key until the wipers of the switches are restored to their normal position.

In the event that the circuit interrupter operates under automatic control, an alarm signal is given to the dispatcher and he may ascertain the unit that is operated by operating a manual control key, in the same manner as before.

In the event that the key which enables the switches to be operated automatically is actuated under the` above conditions, the wipers of both switches are rotated until they assume a position corresponding to the operated unit. In this manner, the dispatcher is apprised of the operation. I-Ie will then restore the switches to their normal position by the operation of the manual control key.

While, in the drawing, I have shown a plurality of batteries, it will be understood that there is, preferably, but one battery at the substation and another at the dispatchers cnice. For convenience, the batteries have been shown grounded. However, it will be obvious that a metallic circuit may be used.

Referring now to the drawing, at A is shown a telephone station of the usual type. A rotary switch RS is of the usual type, whose wipers move in a forward direction only under the control of a motor magnet 1. The rotary switch RS is provided with three wipers 2, 3, and 4. Each wiper is adapted to engage a bank contact set of twentyfive contacts.

Keys K and K-l are of the usual single-throw non-locking type well known in the telephone art and are provided for the purpose of controlling circuit interrupters at the substation. The key K-2 is of the single-throw, non-looking type and is provided with springs 5 and 6. The keys K-3, K-4 and K-5 are of the usual type, the key ISI-3 being constructed so as to lock in operated position.

The key K, when operated, is adapted to force a spring '7 into engagement with its working contact, thereby connecting ground to all the bank contacts accessible to the wiper 2, except bank contacts 8 and 9. The key Ke-l, when operated, is adapted to force a spring 10 into engagement with its working contact, whereby ground is applied to all the bank contacts accessible to the wiper 3, except the bank contact 11. The key K-4 is adapted to operate a spring 12 and is a synchronizing key. The key K-2 is adapted to control the energization of a line relay 13 and will be termed a manual control key.

The line relay 13 is a relay of ordinary type and controls an armature 14. The stepping magnet 1 is adapted to advance the wipers 2, 3 and 4 upon its deenergization. The magnet 1 also controls an armature 15. Relays 16 and 17 are of the usual type. The relay 16 is provided with armatures 18 and 19. The armature 18 is adapted to complete the circuit of an audible alarm 19.

The relay 17 is provided with armatures 20 and 21. The key K-6, when operated, is adapted to force a spring 22 into engagement with its working contact and to force the spring 22 out of engagement with its resting contact. All the bank contacts accessible to the wiper 4, except the bank contact 23, are connected together to a signalling lamp 24. The bank contact 8 is accessible to the wiper 2 and is connected to a signalling lamp 25.

The station A is provided with a push-button 26. The dispatchers ofce is connected to the substation by means of a four-conductor trunk line comprising conductors 30, 31, 32 and 33 with a ground return. The conductors 30 to 32, inclusive, terminate in Wipers 35 to 37, inclusive, of the rotary switch RS-l at the substation. The conductor 33 is connected to a line relay 38 that is adapted to operate an armature 40. The armature is connected to a stepping magnet 41 and operates the wipers 35 to 37, inclusive, of the rotary switch RS-l upon its deenergization. Each of the wipers 35 to 37, inclusive, of the rotary switch RS-l has access to twenty-five bank contacts.

The bank contacts 42 and 43, accessible to the wiper 35, are connected to battery, the bank contact 43 being connected to battery through a resistor 44. The remaining bank contacts, accessible to the wiper 35, are connected to relays, such as 45 and 46. The relays 45 and 46 control armatures 47 and 48 which extend to relays, such as 49 and 50. The relays 49 and 50 control armatures 51 and 52 which extend to the closing coils of the circuit breakers C and Cl, respectively. The circuit breakers C and C-l are of the usual type and may perform any desired function at the station.

When the circuit breaker C is closed, a switch 54 is operated into the opposite position from that shown. During the operation of the circuit breaker, battery is momentarily connected to a common relay 55 by means of springs 56, 57 and 58 by the momentary simultaneous connection of springs 57 and 58 with spring 56. The relay 55 controls an armature 57 that is connected to a bank contact 58 accessible to the wiper 37. The bank contacts accessible to the wiper 36, with the exception of the bank contact 59, are connected to relays, such as 66 and 6i. The relays 60 and 61 control armatures 62 and 63 that extend to the tripping coils of the circuit breakers C and C-1, respectively. Relays 64 and 65 are associated with the power apparatus at the substation and are controlled in any well known manner, such as a short-circuit in the associated power line. They are adapted to cause the tripping operation of the circuit breakers C and C-l.

The telephone substation B is of the usual type and is provided with a push-button 66 whereby the station A may be signalled.

While I have shown circuit interrupters at the substation controlling the operation of the selective apparatus, it will be obvious that the selective apparatus may respond to the operation of other devices.

Having described the apparatus shown in the drawing, l will now describe its detailed operation. For this purpose, it will be assumed that the apparatus is in the position shown and that the dispatcher desires to close the circuit breaker C. To accomplish this result, the dispatcher will operate the manual control key K--Z twelve times, the thirteenth set of bank contacts of the rotary switch RS--l at the substation being connected to the circuit breaker C.

Each time the key K-2 operates, a circuit is completed extending from ground by way of spring 5 and its working contact, line relay 13, working contact of spring 6 and said spring, trunk conductor 33 and line relay 38 to battery. The line relay 13 is energized over this circuit to complete a circuit for the motor magnet 1. The motor magnet 1 operates to position its pawl so as to actuate the switch shaft carrying the switch wipers 2 to 4, inclusive, upon its deenergization and to operate the armature 15. The operation of the armature 15 is without particular function at the present time.

lThe energization of the line relay 38 at the substation completes a circuit for the motor magnet 41. The motor magnet 41 operates to position its pawl. When the key K-Z is released, the circuits of the line relays 13 and 38 are opened and these relays are deenergized.

As a result of the deenergization of the relay 13, the circuit of the magnet l is opened and this magnet is deenergized to advance the wipers 2 to 4, inclusive, into engagement with the second set of bank contacts.

The deenergization of the line relay 38 at the substation opens the circuit of the magnet 41 which is deenergized to bring about the actuation of the switch wipers 35 to: 37, inclusive, into engagement with their second set of banks contacts.

In this position of the switch wipers, a circuit is completed extending from battery by way of resistor 44, wiper 35, trunk conductor 30, wiper 2, bank contact 8 and signalling lamp 25 to ground. The signalling lamp 25 is lighted over this circuit. This is an indication to the dispatcher that the switch wipers of the rotary switches RS and RS-l are in the same relative position with respect to their bank contacts.

As the key K--2 is operated, the wipers 2 to 4, inclusive, are stepped in synchronism with the wipers 35 to 37, inclusive. When the wipers 2 to 4, inclusive, arefbrought into engagement with their `thirteenth set of bank contacts, the wipers 35 to 37, inclusive, will be in engagement with their thirteenth set of bank contacts and the dispatcher will know that the connection is extended to the circuit breaker C.

As the circuit breaker C has been assumed to be open, there will be a circuit completed eX- tending from battery by way of pallet switch 54, resistor' 6'?, bank contact 68, wiper 37, trunk conductor 32, spring 22 and its resting contact, wiper 4,*bank contact with which said wiper is in engagement and signalling lamp 24 to ground. The signalling lamp 24 is operated over this circuit to indicate to the dispatcher that the circuit breaker C is in an open position.

In order to close the circuit breaker C, the dispatcher will operate the key K. By reason oi this operation, a circuit is completed extending from ground by way of spring '7 and its working contact, bank contact with which wiper 2 is in engagement, said wiper, trunk conductor 3Q,

wiper 35, bank contact 69 and relay 45 to bat- Y tery. The relay 45 is energized to complete a circuit, at armature 47, extending from ground by way of front contact and said armature, relay 49 and pallet switch 54 to battery. The relay 49 is energized over this circuit and operates to complete a circuit for the closing coil of the circuit breaker C at armature 5l. In this manner, the circuit breaker C is closed.

As a result of this operation, the circuit of the relay 49 is opened and this relay is deenergized. Another result of the operation ofv the circuit breaker C is that the battery connection is removed from the bank contact 68, accessible to the wiper 37, and the signalling lamp 24 at the dispatchers cnice is extinguished. In this manner, the dispatcher is apprised of the operation oi the circuit breaker C.

The relay is, of course, momentarily energized by the operation of the circuit breaker C. However, inasmuch as the wipers 35 to 37, inelusive, are not in their normal position, this operation is without function at the present time. The dispatcher will now restore the switches to their normal position by intermittently operatn ing the key K-2 in an obvious manner.

Had the circuit breaker C been closed under the foregoing conditions, there would have been no battery potential connected to the bank contact 68 in the first instance and, consequently, the signalling lamp 24 would not have been lighted. v

To trip the circuit breaker C, the dispatcher will operate the key K-L As a result of this operation, a circuit is completed extending from ground by way of spring 10 and its working contact, bank contact with which wiper 3 is in en gagement, said wiper, trunk conductor 3l, wiper 36, bank contact 70, relay and pallet switch 54 to battery. The relay 60 is energized over this circuit and operates to complete the circuit of the tripping coil of the circuit breaker C.

When the circuit breaker is tripped, the relay 55 is, of course, momentarily energized and this operation is again without function. By the cperation of the circuit breaker C, a battery potential is placed upon the bank contact 68 and the signalling lamp 24 is lighted to indicate that the circuit breaker has been tripped by the dispatcher. The apparatus is released in the saine nanner as before.

It will be recalled that, when the wipers of the rotary switch RS are in engagement with the second set of bank contacts, which includes the bank contact 8, the testing lamp 25 is lighted to indicate that the switches RS and R53- l are in synchronis'rn. Should switches be out oi synchronisin, the lamp 25 will not be lighted by reason or. the fact iat insufficient current traverses the circuit which includes relays, such as 45. The two being in series, the current is insucient to either light the lamp or energize the relay.

As the lamp 25 is not lighted, the dispatcher is informed that the switches are out of synchronisrn. The dispatcher will now operate the key K--4 a plurality of times to bring the wipers of the rotary switches RS and RS-i into synchro nism, or into the same relative position with respect to their bank contacts. As a result of this operation, a circuit is completed extending from ground by way of working contact of spring l and said spring, trunk conductor 3S and line relay B8 to battery. rEhe relay 38 operates to complete a circuit for the stepping magnet 4l.

By intermittenty operating the synchronizing key Kw4, the dispatcher is enabled to step the wipers 35 to 37, inclusive, of the rotary switch RS-i without stepping the wipers of the rotary switch Consequently, the dispatcher may operate these 'wipers until they are brought into engagement with the second sot of bank contacts, which includes the contact 43. By this operation, the testing lamp 25 is illuminated and the dispatcher is apprised oi" the fact that the switches are now in synchronism.

It will now be assumed that the wipers of the switches RS and RS-l are in their normal po sitions and that the circuit breaker C operates under automatic control of the overload relay 64. As a result of this operation, the relay 55 is momentarily energized. A circuit is now comn pleted extending from ground through the lower winding of relay 55, front contact and armature 57', bank Contact 58', wiper Si, trunk conductor S2, spring 22 of key K14-5' and its resting contact, wiper 4, bank contact 23, relay 1'?, bank contact 9, wiper 2, trunk conductor 35, wiper 35 and bank contact 42 to battery. The relays 55 and 17 are energized over this circuit.

The relay l'? operates to complete a holding circuit for itself at arma-ture 2l and to close a circuit for the relay 16 at armature 26. The relay 16 operates to establish a locking circuit for itn self at armature i9 and to close a circuit for the audible alarm lo at armature i8. The operation of the alarm draws the attention of the dispatcher to the fact that an operation has been performed at the station. The dispatcher may ascert n what apparatus unit has operated in substantially the same manner as before. l'n order to stop the operation of the audible alarm i9', the dispatcher will operate the key K-5, thereby opening the locking circuit of the relay 16.

Should dispatcher have the key K-B operated in order that the selector switches operate automatically, when the circuit breaker C is operated by automatic devices, vthe operation is slightly different. The relay l5 is energized as before, oi course, to cause the opV audible alarm i9. ln addition, a circuit is completed which extends from ground through the lower winding of the relay' 55, bank contact 58', wiper 37, trunk conductor 32, spring 22 and its Cil resting contact, spring of key K-3, line relay l3, armature l5 and its back Contact and line relay 38 to battery. The relays 13 and 38 are energized in series.

The relay 13, upon being energized completes a circuit for the stepping magnet l. The magno` l operates to position its pawl and, at armature i5, opens the circuits of the line relays 13 and 33. The relay 13 is deenergized to open the circuit of the magnet l, which is deenergized to advance the switch wipers one step and to complete another circuit for the relay 13.

The operation of the relay 3S causes the operation of the magnet Li1 to advance the wipers 35 t0 37, inclusive, one step.

When the wipers of the rotary switches are stepped into their second position, the circuit of the relay 55 is opened and this relay is deenergized. The line relays 13 and 33 are energized over a circuit which extends from ground through the signalling lamp 2e, wiper Ll, springs of key K-3, line relay i3, armature l5 and its back contact, trunk conductor 33 and relay 38 to battery.

The automatic operation oi the motor magn ts 1 and Li1 continues in the manner described until the wipers 35 to 37, inclusive, are broug. t into engagement with the set of bank contacts to which is connected the circuit breaker that is operated by automatic control. As this has been assumed to be the circuit breaker C, battery potential will be applied to the bank contact 68 and a circuit will be completed extending from battery at the auxiliary switch 54 of the circuit interrupter C by way of wiper 37, trunk conductor 32, spring 22', Wiper 4 and signalling lamp 24 to ground. This circuit shunts out the line relays 13 and 38 and, a the same time, causes the lamp 24 to be more brightly lighted, thus indicating that the circuit breaker C is the one that has been tripped.

ln order to restore the rotary switches to normal under these conditions, the dispatcher will operate the step-over key K-G. As a result of this operation, the short-circuit is removed from the line relays 13 and 33 and these relays arev again intermittently operated to cause the wipers 2 to e, inclusive, of the rotary switch RS and the wipers 35 to 37, inclusive, of the rotary switch RS-l to be brought into engagement with their rst set of bank contacts. In this position, as the relay 55 is deenergized, there is no circuit completed for the line relays 13 and 38 and their operation ceases.

It may sometimes occur that more than one circuit breaker will be operated simultaneously or in quick succession by the operation of automatic devices, and it may be necessary for the dispatcher to operate them in a predetermined sequence, such sequence being oiierent from the order in which they are connected to the bank contacts of the rotary switch R53-1. Under these conditions, the wipers of the switches will be automatically rotated into a position corresponding to the first bank contact to which. a circuit breaker that has been tripped is connected. The line relays 13 and 38 will thereupon be shortcircuited and the rotation of such switches will cease. By operating the step-over key K-, the dispatcher may remove the shunt circuit from the line relay 13 at spring 22 and cause the wipers of the switches to be automatically stepped into the next position. The spring 22 shunts armature l5 so that the stepping magnets are energized once. The key K-S is then returned to its original position and the wipers are moved until they assume a position corresponding to the position to which another circuit breaker that has been tripped is connected. Thus, the dispatcher may connect with the unit he desires. The operations proceed as before.

1n some instances, the dispatcher may desire to maintain all the circuit interrupters in a particular substation in their closed positions. This may be accomplished by the operation of the selective apparatus. To maintain all the circuit interrupters in the station in their closed positions, the dispatcher will throw the automatic control key K-3 and will then operate the key K.

Now, when the circuit interrupter C at the substation is tripped under the control of automatic devices, such as 64 and 65, the wipers of the rotary switches RS and RS-l are operated in synchronisrn until the Wipers 35 to 37, inclusive, of the rotary switch RS-l are brought into engagement with the bank contact set which includes the bank contact 68. The wipers 2 to 4, inclusive, ci the rotary switch RS at the dispatchers oilce are stopped in engagement with the corresponding bank contacts.

Inasinuch as the key K has been operated, there is a circuit completed for the relay 45. The circuit interrupter C is thus closed by the operation of the relay 4:9 and the battery potential is removed from the bank contact GL, whereby the short-circuit is removed from the relays 13 38. These relays are now operated in a manner before described to advance the switch wipers to their normal position. By the provision of these circuit arrangements, it is possible for the dispatcher to control the apparatus in the substation with a minimum of attention.

In the event that the dispatcher desires to talk with an operator at the substation, he will operate the push-button 26 associated with the telephone substation A. As a result of this operation, a circuit is completed extending from ground by way of working Contact of spring 26 and said spring, bank contact 11, wiper 3, trunk conductor 3l, wiper 36, bank contact 59, spring 66 and its resting contact, and the ringer at substation B to battery. The ringer at substation B is now actuated to indicate to the operator that the dispatcher desires to converse with him. W hen the receiver is removed at the telephone substations A and B, the conversation may be carried on in the usual manner. The operation is identically the saine when the operator at the telephone station B desires to converse with the dispatcher.

My invention is not limited to the particular arrangement or the apparatus illustrated and described, but may be variously modined without departing from the spirit and scope thereof, as set forth in 'the appended claims.

I claim as my invention:

1. In a supervisory control system, a first station, a second station, automatically-operated apparatus units at said second station each operable to a plurality oi positions, synchronouslyoperated means at said and said second station, rneans including .said synchronously-operated means fcr controlling said ap oaratus units, means including said synchronously-operated means for indicating the operation of said units at said rst station, said synchroncusly-operated means being normally non-operative, and means whereby upon the automatic operation of one oi said units said synchronously-operated means is started into operation.

2. 1n a supervisory control system, a first sta- Cir tion, a second station, automatically-operable apparatus units at said second station, normally non-operable selectors at each `of said stations, means responsive to the operation of any one of said apparatus units for starting said selectors into operation, means for .maintaining said selectors in operation to select the operated unit, a signalling means at said iirst station, means including said selectors following a selection oi the operated apparatus unit for operating said signalling means in accordance with the operation of said unit, and means including said selectors for selectively operating said apparatus units from said iirst station.

3. In a supervisory control. system, a iirst station, a second station, a signalling line connecting said stations, apparatus units at said second station, means for operating said units automatically, selectors at each of said stations, said selectors being normally in a non-operating condition, means responsive to the operation of any one of said apparatus units for starting said selectors into operation for sequentially connecting said apparatus units to said signalling line, means following a connection of one of said apparatus units with said signalling line for operating said unit from said first station, signalling means at said first station and means including said selectors for operating said signalling means responsive to the operation of said apparatus unit.

4. In a supervisory control system, a rst station, a second station, a plurality of apparatus units at said second station, a rotatable device at each of said stations normally in a non-operating condition, means responsive to the-operation of any one of said apparatus units for starting said rotating devices into operation, means for maintaining said rotating devices in synchronism, a signalling Vline connecting said stations sequentially switched from one to another of said apparatus units as said rotated devices are rotated in synchronism, means including said signalling line and said rotatable devices for selectively operating said apparatus units from said first station, a second signalling line connecting said stations sequentially switched from one to another of said apparatus units by said rotating devices, signalling means at said first station, and means including said rotating de-` vices and said second line for operating said signalling means in accordance with the operation of said apparatus units.

5. In an electrical control system, a iirst station, a second station, a plurality of automatically-operable apparatus units at the second station, selectors at said stations, means at the rst station whereby the selectors may be started into operation and operated synchronously to select any one of said apparatus units, means at the iirst station controlled jointly by said selectors following the initiation of their operation for indicating when said devices are in or out of synchronism, signalling means at the rst station for indicating the condition of the apparatus units, means including the selectors in selecting position for operating said signalling means in accordance With the condition of the selected unit, and means responsive to the automatic operation of any one of said apparatus units for starting the selectors into operation, said means for indicating the synchronous or non-synchronous operation of the selectors being also responsive to the automatic operationof the selectors.

6. In an electrical control system, a first station, a second station, a plurality of automatically-operable apparatus units at the second station, normally non-operating selectors at said stations, signalling means at the first station, means responsive to the operation oi" any one of said apparatus units for operating the selectors in synchronism to select the operated unit and operate the signalling means in accordance with the condition oi the operated unit, and means at the rst station operable to thereafter eiect the continued operation of the selectors to their normal non-operating position.

7. In an electrical control system, a first station, a second station, a plurality of automatically-operable apparatus units at the second station, normally non-operating selectors at said stations operable to a plurality of selecting positions each individual to an apparatus unit, signalling means at the iirst station, means responsive to the operation of any one of said apparatus units for operating the selectors in synchronisrn to a selecting position to select the operated unit and operate the signalling means in accordance with the condition of the operated unit, and means including said selectors in said selecting position for changing the condition of the selected apparatus unit.

8. In an electrical control system, a first station, a second station, a plurality of automatically-operable apparatus units at the second station, normally non-operating selectors at said stations operable to a plurality of selecting positions eachindividual to an apparatus unit, signalling means at the rst station, means responsive to the operation of any one of said apparai tus units for operating the selectors in synchrom'sm to a selecting position to select the operated unit and operate the signalling means in accordance with the condition of the operated unit,

means including said selectors in said selecting 9. In an electrical control system, a iirst stanism to a selecting position to select the operated unit and operate the signalling means in accordance with the condition of the operated unit, means including said selectors in said selecting position for changing the condition of the selected apparatus unit, and means at the rst station operable to effect the release of the selectors from the selecting position whereby said selectors may automatically return to their normal non-operating position.

10. In a supervisory control system, a first station, a second station, a plurality of automatically-operable apparatus units at the second station operable to a plurality of positions, normally non-operating selectors at said stations operable to a plurality of selecting positionseach individual to an apparatus unit, means for operating said selectors in synchronism from the iirst station to a selecting position to select any one of said apparatus units and to return the selectors to their initial non-operating position, signalling' means at the rst station, means including the selectors in said selecting position responsive to the selection of a unit for operating the signalling means at the rst station in accordance with the condition of the unit, means including the selectors in said selecting position for operating the selected unit from the rst station, and means whereby upon the return of the selectors to their initial non-operating position, said selectors are operated synchronously to select any one of the apparatus units which has automatically operated.

11. In a supervisory control system, a first station, a second station, apparatus units operable to a plurality of positions at the second station, a plurality of line conductors connecting the stations, selectors at said stations operable to a plurality of selecting positions each individual to an apparatus unit, means including one of said line conductors for operating the selectors in synchronism to a selecting position from said iirst station to select any one of said units and for maintaining the selectors in said selecting position, signalling means at the rst station operable over said selectors in said selecting position and a second of said line conductors to indicate the condition of the selected unit, means including said selectors in said selecting position and a third line conductor for operating the selected unit to one position, and additional means including said selectors in said selecting position and a fourth line conductor for operating the selected unit to'another position.

12. In a supervisory control system, a first station, a second station, apparatus units operable to a plurality of positions at the second station, a plurality of line conductors connecting the stations, selectors at said stations operable to a plurality of selecting positions each individual to an apparatus unit, means including one of said line conductors for operating the selectors in synchronism to a selecting position from said iirst station to select any one of said units and for maintaining the selectors in said selecting position, signalling means at the first station operable over said selectors in said selecting position and a second of said line conductors to indicate the condition of the selected unit, and means including the selectors in said selecting position for selectively operating the selected unit from the first station.

13. In an electrical control system, in combination, a iirst station, a second station, automatically-operable apparatus units at the second station each operable to a plurality of positions, selectors at said stations, means for operating said selectors synchronously to effect successive selections of the apparatus units, signalling means at the first station responsive to the condition of the units and the position of the selectors, and means responsive to the automatic operation of any one of said units for initiating the operation of the selectors to eiiect the selection of the operated unit and the operation of the signalling' means at the rst station to indicate the condition of the selected unit, and means including the selectors for operating the selected unit.

14. In a supervisory control system, a rst station, a second station, a plurality of automaticallyoperable apparatus units at the second station operable to a plurality of positions, normally non-operating rotary selector switches at said stations, means for operating said selector switches synchronously to select any one of said units, means including a circuit over said selector switches for operating a selected unit, signalling means at the rst station operable over a circuit including said selector switches to indicate the condition of the selected unit, and means at the rst station operable to render the selector switches automatically operable to select any one of said apparatus units which operates automatically.

15. In a supervisory control system, a first station, a second station, a plurality of automatically-operable apparatus units at the second station operable to a plurality of positions, normally non-operating rotary selector` switches at said stations, means for operating said selector switches synchronously to select any one oi said units, means including a circuit over said selector switches for operating a selected unit, signalling means at the rst station operable over a circuit including said selector switches to indicate the condi-tion of the selected unit, additional signalling means at the rst station operable in response to the automatic operation of any one of said units, and means responsive to the automatic operation of any one of said units whereby the selector switches are started into operation to select said automatically operated unit.

16. In a supervisory control system, a first station, a second station, a plurality of automatically-operable apparatus units operable to a plurality of positions at the second station, selector switches at said stations having a plurality of selecting positions each individual to an apparatus unit, means at the rst station for operating the selectors step-by-step in synchronous relation to select any one of said apparatus units, signalling means at the rst station operable over a circuit including the selector switches in any selecting position to indicate the condition of any selected unit, means at the first station individual to each of the units and including the selector switches in selecting position for operating a selected unit, said selector switches being normally non-operative and automatically operable in response to the automatic operation of any one of said units to select the operated unit, and signalling means at the first station operable in response to the automatic operation of any one of the units while the selector switches are in the non-operative position to signal the occurrence of an automatic operation of one of the units.

HARRY E. WULFING. 

